datagridview 单元格 vb.net 的空值
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Null Value for datagridview cell vb.net
提问by shaik ibrahim
How to get for null value in datagridview i did this in the cell validation event but it dosent seem to work. I want the user to add a new row and someone force him to give an ID or delete the row. What am i doing wrong. This is not a how to do question. This is a what is wrong Question. So right now it detects null but once i corrected the cell it still dosent allow me to get out of the row.
如何在 datagridview 中获取空值我在单元格验证事件中执行了此操作，但它似乎不起作用。我希望用户添加一个新行，有人强迫他提供 ID 或删除该行。我究竟做错了什么。这不是一个如何做的问题。这是一个什么是错的问题。所以现在它检测到空值，但是一旦我更正了单元格，它仍然允许我离开该行。
If DataGrid.CurrentCell.ColumnIndex = 0 Then
If IsDBNull(DataGrid.CurrentCell.Value) Then
Msgbox("Cannot be Null")
e.cancel = true
ElseIf Not IsDBNull(DataGrid.CurrentCell.Value) Then
e.cancel = False
End If
End If
回答by shaik ibrahim
So i tried this and it works for me . it simply uses e.formatedvalue. Current Cell Value is the cell value before and after edit while formatedvalue is what is being typed it . i guess i understand now so here is the coding
所以我尝试了这个，它对我有用。它只是使用 e.formatedvalue。Current Cell Value 是编辑前后的单元格值，而 formatedvalue 是正在输入的值。我想我现在明白了，所以这里是编码
If grdDataGrid.CurrentCell.ColumnIndex = 2 Then
If e.FormattedValue = "" Or IsDBNull(e.FormattedValue) Then
MsgBox("Cannot be Null")
e.Cancel = True
Exit Sub
End If
End If
They are also different ways like adjusting your column properties to not allowed null but since the column properties inherit from the database i decided to use this.
它们也是不同的方式，例如将列属性调整为不允许为空，但由于列属性从数据库继承，因此我决定使用它。
回答by Richard Binning
Another way around this would be to explicitly set the default null value for the new datagrid cell to the value you are checking for. For instance,set the null= to an empty string if you are pulling string values. You can use the properties palette to set this.
解决此问题的另一种方法是将新数据网格单元的默认空值显式设置为您正在检查的值。例如，如果您要提取字符串值，请将 null= 设置为空字符串。您可以使用属性选项板进行设置。
回答by matzone
I think this should be works ...
我认为这应该是有效的......
If DataGrid.CurrentCell.ColumnIndex = 0 Then
If IsDBNull(DataGrid.CurrentCell.Value) Then
Msgbox("Cannot be Null")
e.cancel = true
exit sub
End If
End If
